Electromechanical valves are used in large numbers in a wide variety of fluid and gas flow control applications. Desirable properties for such valves are;
low leakage, PA1 fast response time, PA1 low power consumption, PA1 long life, PA1 low cost, PA1 ability to open with high pressure difference across the valve.
The most common type of prior art electromechanical valve is actuated by a solenoid. Solenoid actuated valves have a definitely limited life, may use significant power, are slow to respond except in small sizes, and require special design if they are to be capable of opening with high pressure difference across the valve. The present invention does not have these shortcomings; it uses little power, responds quickly, opens easily with high pressure difference across the valve, is inexpensive, and is believed to have practically unlimited life. These attributes make it suitable for general application, but particularly suitable as a pulsed expansion valve for refrigeration and air conditioning (U.S. Pat. No. 4,459,819). A pulsed expansion valve must function reliably for years, be very inexpensive, be capable of opening with a pressure difference of at least 300 psi, have fast response to actuating voltage, and have very low leakage. No prior art electromechanical valve has all these properties. For this reason, among others, pulsed expansion valves are not in common use despite their energy saving advantages. The present invention therefore meets a hitherto unmet condition for a practical pulsed expansion valve.